Battery seal composition



July 29, 1930. 1,771,775

L. M. CURRIE BATTERY SEAL COMPOSITION Filed May 10, 192'! Patented July 19 30 TA-T ES PATENTLOFFWE LAUGI-ILIN M. CURRIE, oriznxnwoononio, assisnort To NATIONAL cannon co, 11m,

' A eoaronirrro v OF NEW YoRK BATTERY snAr-eomrosirroiv Application filed May 10,

This invention relates to improvements in thermoplastic compositions for use in sealing dry cells and dry cell batteries. A composition which has been rather generally used to sealdry cells and dry cell batteries is a mix- I ture of rosin and a' mineral filler. Usually small amounts of lime for strengthening purposes, and coloring' matter are also present. Seals of this composition show a pronounced tendency to crack when subjected I" to suddenand extreme temperature changes. i

vention.

Such cracking is accentuated when lime is present and particularly when such seals are poured upon an asphaltic subseal base, as i is the practice with somebattery manufacturers; i

In my eopending application Serial No. 190,280 filed May 10,1927, 1 have disclosed the addition of'certain-materials to rosinmineral filler sealing'compositions for the purpose of imparting thereto toughness and ability to withstand wide and sudden temperaturechanges without cracking and also to improve other properties thereof. Similar objects are comprehended'by tliepresent in- The figure of drawing, is a perspective view of a battery partly broken away.

According to the present invention small percentages of certain drying oils, preferably fin conjunction with small amounts of certain additional materials hereinafter to be de scribed, are added to the rosin-mineral filler composition. The drying oils which have been found suitable for the present purpose are Chinese wood oil or tung oil, soya bean oil, linseed oil, and perillaoil.

In general, the amount of oil and other treating agent required to produce the desired results will be less than 3% by weight of the seal being treated. The amount required will vary considerably depending upon the composition of the rosin-mineral filler seal being treated, and particularly with respect to the lime content thereof. A seal containing a relatively high lime content, for example 1% or more, will require a relatively large addition of treating agent to remove brittleness and insure toughness, whereas with a relain cold storage at 09 seal.

192?. Serial No. 190,281

t'ively low lime content much smallerpquantities are effective, I I a 'Proportions of glycerine or other poly-- hydric alcohol equal to or less than the pro portion of tung or other oil used are preferably added with the oil. 1 Best results are, obtained when a small percentage of ametallic soap, such as lead tungate,lead linoleatei, or lead resinate, is-also present. The treating-addition mayalso contain minor. amounts of, paraffin or a paraffin oil. Further the substitution. of castor oil for. the glycerine component is not precluded. i i. f

The following comparative results indicatev the improvement which may he obtainedby 1 the use of treating'additions of the class at; scribed: 1 .1 y 'I- r dEacampZe No.

" One lot of batteries sealed with a composition containin gapproximately equal parts 3% coloring matter and 1 cracking of the seal. the batteries showed after 21 days the had cracked. i 1 i Another lot' of batteries similar [in every. respectexcept that0.5'% glycerine, 1.5% tun 011,, 0.17% parafiin, and 0JO1'%'precipitated lead resinate were added to the seal composition, was subjectedto identical cold storage conditions and showed no cracking at the end of 21 days in cold storage. l

Example No.

'After 9 days, 60% of cracks in the seal andby weight of rosin and mineral matter, about lime, was placed- C., andobserved for i 1 seal-on 67% of the batteries V g so.

Two lots. of batteries sealed with approximately the same-rosin-mineral filler composition as specifiedin Example No.11, but with the seal-treating addition ofthe'tre'ated lot consisting. of 1.0% and 0.015% subjected to similar improvements in favor of the treated Of the lot containinguntreated seal, the seal on 16% crackedin a days, in 7 days. None of the lot on. which tun'g. oil-glycerine-treated seal was used showed cracks at the end of 7 days in cold storage.

glycerine, 1.2% tung on". precipitated lead resinate, when cold storage conditions, showed;

and23.5%

In both of the examples above mentioned ample, While rosin has been specified above,

other respects than those indicated, and particularly as to pouring properties, and freedom from pits and air bubbles. The untreated seal was poured with some difficulty and requireda temperature of about 181C, to permit of pouring with any degree of success. The untreated'seal Was alsocharacterized by the presence of bubbles, with of 'the batteries requiring retorching, whereas the oil-treated seal poured smoothly and even 1y at 174 (3., with only 8% requiring retorching. In addition to the above-mentioned improved properties which are poss essedbythe treated seal as compared with the untreated seal, it is to be noted that tliextreated seal hasimproved finishand luster." It is fun ther to be noted that the molten treated seal wets the brass terminals and other metallic portions ofthe cells with which itcomes' in contact much more readily than does the untreatedseal composition, thus insuring more perfect sealingat these surfaces ofcontact,

Referring to the drawing, numeral l denotes abattery boxlfor'casing which may be made of cardboard, wood or other suitable materiall', Cells2 arearr'an'ged in the casing and are preferably compactly assembled in three rows of five cells each. Connectors 3 join'the cells in series and external terminals 1 and'5 are provided.

WVhen the cellsare properlyv assembled in" the casing,aninsulating asphaltic sealing compoundis ma'de 'fiuid byheating' and is poured about the cells, preterably'in quantity sufficient to completely embed them and ,to' extend over their: tops" to form aolayer of substantial thickness thereon, as indicated at 6; After the asphalticjsub-seal 6 is solidified a finish layer 7 of sealing material composition of the kind more specifically described above is poured over the sub-seal to fill the casing substantially to the top. I V

The invention is shown in-jthe' drawing as applied toa; conventional form of battery used in radio communication It is to be understood, however, that it snot llmited 1n application to this type ofbatte'ry and may be applied'in sealing other types of batteries as well as single cells. j

It is also to be understoodthatvarious modifications may be made in the proportions "and kinds of'mate'rials us'edin forming the .rosin-mineral'filler composit on which forms the base'for my new composition. For exitfw'ill be understood that equivalent natural and artificial resins may be substituted. It Will'also be'understood that various mineral materials may be used to make up the mineral fillercomponent. Mineral filler materials which'have'been usedsuccessfully in making -up my improved seal composition are sandand ground, fibrous asbestos in the proportions of about 36%fand 10% by weight, respectively, of the seal composition.

I claim:

'1. A sealing composition containing up to about 1% lime, up to about3% Chinese wood oil and glycerine, up to 1% coloring matter, with the balance consisting of about equal parts of rosin and mineral filler.

2. A battery seal composition consisting principally of rosin and a mineral filler and includingupto about 1% of a drying oil and ime.

3. 'A battery seal composition containing up to about 1% lime, up to about 3% of a drying oil and glycerine, up to 1% coloring matter, with the balance consisting of about equal parts of lOSinfiDd mineral filler.

1 A battery seal composition consisting principally of a resin and a mineral filler and including minor proportions of Ghinesewood oil, glycerine and lime.

'5. A battery seal composition containing approximately95% of rosin and mineral filler,up to about 1% lime, and up to about 3% of Chinese wood oil, with the balance principallyv coloring matter.

6. A battery seal composition containing approximately 95% of rosin and mineral filler, up to about 1% lime, and up to' about 3% of Chinese Wood oil and glycerine, with the balance principally coloring matter.

7 A battery seal composition having approximately the following composition: 0.5% glycerine, 1.5% tung oil; 0.17% parafiin; 0.01% lead resinate; and up to 1% In testimony whereof, I afiix my signature.

LAUCHLIN M. CURRIE. 

